[clang] [flang] [flang] Add support for -finit-local-zero (PR #159788)

[Daniel Chen via cfe-commits]

DanielCChen wrote:

Hello @NimishMishra and all reviewers,

I put PR https://github.com/llvm/llvm-project/pull/216164 in ready to review. Thanks to @MattPD @tarunprabhu and @eugeneepshteyn for the very valuable comments. 

The `-finit-local=zero` mode in PR #216164 should supersede this PR. with an exception that it doesn't yet initialize CHARACTER type array as documented as a known limitation. We can look into that as a subsequent PR.

Please let me know if you have any concerns or suggestions. Always appreciate it.


https://github.com/llvm/llvm-project/pull/159788